Several factors that determine the normal displacement of an air compressor

The displacement of an air compressor is actually a manifestation of the quality and efficiency of the equipment to a certain extent, and it is usually affected by several factors.

  1. Leakage: There will be gaps between the rotors and between the rotor and the housing during operation, and they are not in direct contact, so gas leakage will occur. When the pressure increased gas leaks through the gap to the suction pipe and the sucking groove, the exhaust volume will be reduced. Therefore, to minimize leakage, seal teeth are made on the tooth top of the driven rotor, seal grooves are made on the root of the drive rotor, and ring or strip seal teeth are machined on the end surface. But if the sealing line is worn out, the leakage will increase and the exhaust will decrease.

   2. Suction state: The screw compressor is a positive displacement compressor, and the suction volume remains unchanged. When the suction temperature rises, or the suction pipe resistance is too large to reduce the suction pressure, the density of the gas decreases, and the gas exhaust volume is reduced accordingly.

  3. Cooling effect: When the gas is compressed, the temperature will rise, and the temperature of the rotor and casing will also rise. During the suction process, the gas will be heated by the rotor and the casing to expand, reducing the suction volume. The rotor of an air compressor is sometimes cooled by oil, and the casing is cooled by water. The main reason is to lower the temperature. If the cooling is poor, the temperature will increase and the exhaust gas will decrease.

  4. Rotation speed: The displacement of screw compressor is proportional to the rotation speed. The speed will vary with the voltage and frequency of the grid. When the voltage is reduced (for asynchronous motors) or the frequency is reduced, the speed will drop and the air volume will decrease.

   Therefore, to control the displacement of an air compressor, we must first know its influencing factors, so as to work out the most suitable operation plan.